The present invention relates generally to vacuum cleaners and more particularly, to air filter bags for vacuum cleaners.
Vacuum cleaner filter bags have been provided with numerous collar configurations for interfitting with inlet ducts carrying dirt laden air into the bags. These collars have been formed of materials such as cardboard, rubber, leather, plastic and/or combinations of some of these materials. In order to successfully function, a bag collar must be properly positioned and retained in position relative to an air inlet duct, and the bag collar must have a good air seal established between itself and the inlet duct so as to prevent dirt laden air from bypassing the filter bag.
It is known to fabricate filter bag collars of a plastic material as a way of reducing manufacturing and material cost. Plastic collars have been fabricated with sealing lips adjacent to an aperture in the collars for sealing with the outer periphery of circular air ducts. Retention of the collar on the duct with such collars is accomplished by the frictional engagement of the collar and duct with a rib or stop often being provided on the duct to prevent slippage of the collar from the duct.
It is also known to provide such plastic collars as described above with a molded annular rib spaced radially outward from the aperture to provide the collar with a face seal for use with air ducts having a flange-like or non-tubular configuration at its interface with the collar. However, such arrangements utilizing a flange-like air duct arrangement require a means to retain the collar in position against the duct in order to establish a seal therewith. Such means is generally in the form of a slotted holder into which the collar slides with the holder being attached to or formed integrally with the inlet air duct.
It would be desirable to develop a new and improved filter bag collar arrangement which could provide an air seal with a flanged inlet air duct. Further, it would be desirable to provide such a filter bag collar arrangement which would establish an air seal without requiring a separate holder on the duct for retention and thereby reduce the fabrication expense of the air duct.
Filter bag collars generally provide a single air seal with an air duct although some collars have more than one sealing means with each sealing means being used for different air duct configurations. However, it would be desirable to develop a new and improved filter bag collar with dual sealing capability; that is, a collar that could provide two seals which are usable simultaneously to further assure that a positive air seal is established between the filter bag and duct.